It’s fitting that he did this at Mt. Wilson. So many discoveries of the Sun were made at Mt. Wilson, like that sunspots are cooler areas of the sun, and that they exhibit heavy magnetic fields (first time magnetic fields were ever detected outside of Earth). Also discovered there were the polarity shift of magnetic fields in the sunspot, the fact that the Sun doesn’t rotate the same rate among different latitudes, and the five-minute oscillation of the entire Sun.

He also mentioned that he had fantastic seeing at Mt. Wilson. That’s actually the observatory’s best physical quality; it is among the locations with the best seeing in North America. It’s a shame the light pollution shut down the deep sky science.

Of the prominent dark areas, the one on the bottom left is really interesting. Zoom into the high-res version, and it looks for all the world like magnetic force lines around a bar magnet. Would love to know precisely what’s going on there.

They probably are magnetic field lines. Sunspots are regions of intense magnetic fields and it’s the magnetic fields that are disrupting the convection of the Sun which makes them cooler. It’s probably the charged plasma following the magnetic field lines. Sunspots do have a magnetic north and south polarity, although you usually don’t see them as two distinct spots. SOHO and SDO satellites have images that show the magnetic polarity.

@5, Rachel, it IS plasma following magnetic field lines.
The sun is a set of massive dynamos that generate incredibly strong magnetic fields. Those dynamos are caused by “rivers” of plasma far below the “surface” and convection cells that distort them. That causes the magnetic fields to go from moderately tangled to unbelievably tangled.
It’s those tangles that we see as prominences and other features that give us such beautiful sights.
When those tangles “short out”, they have a part of those field lines disconnect, which gives us flares and CME’s (Coronal Mass Ejection).
There are magnetic field models of the sun, including the dynamos. To call it complex is to make a massive understatement!
But then, the complexities of nature are CRAZY cool! Even when that cool is hot plasma.